Glenn DePriest/Getty Images(NEW YORK) -- Hours after the widow of accused Boston Marathon bomber Tamerlan Tsarnaev said she didn't want to claim the suspected terrorist's body, one of Tamerlan's sisters told ABC News in her first public statement that her family would.

Bella Tsarnaeva said late Tuesday that she and her sister Ailina will plan a proper Muslim burial for Tamerlan, who was killed in a shootout with police days after he and his younger brother Dzhokhar allegedly set off a pair of bombs that killed three people and injured 170 more near the finish line of the Boston Marathon on April 15. Dzhokhar was injured and later captured after a manhunt that shut down the city of Boston.

When the Massachusetts Medical Examiner's Office was ready to release her husband's body, Tamerlan's widow, Katherine Russell, declined to take it herself, according to her attorney.

"It is Katherine Russell's wish that his remains be released to the Tsarnaev family, and we will communicate her wishes to the proper authorities," attorney Amato DeLuca said Tuesday. DeLuca also said Russell has been meeting with law enforcement and is providing "as much assistance to the investigation as she can."

The statement came as investigators said they may have pinpointed a turning point in Tamerlan's growth into alleged radical: a 2012 trip to Russia in which he may have had contact with Russian Islamists.

American officials said they are investigating whether Tamerlan had been in contact over the Internet with a man named William Plotnikov, a Russian-Canadian and a fellow boxer, who had converted to Islam and joined the militant insurgency in the North Caucasus. Plotnikov was killed by Russian authorities while Tamerlan was in Russia, and Tamerlan left the country just days later.

Investigators also want to know what Tamerlan was doing with a known militant recruiter in the region named Mansur Mukhamed Nidal with whom Tamerlan was repeatedly seen leaving a controversial mosque in Makhachkala, the capital of Dagestan. Nidal was also killed by Russian authorities while Tamerlan was in Russia.

But despite what authorities said was photographic evidence the Tsarnaev brothers were behind the Boston bombing and comments reportedly from the surviving brother about how they executed the plot, family friend Britney Smith told ABC News she's not convinced.

"I was always taught to believe what you see and... what I see is two people walking with book bags. I don't see them planting down explosives. I don't see book bags being dropped," Smith said, apparently referring to images widely circulated by the FBI that show the brothers with bags either near or heading in the direction of each of the bomb sites. "If he [Dzhokhar] gets convicted and I see proof of him doing it, then I will be in total shock. I would be in disbelief and disgust that he would do that."